I followed the commenter advise and brought it down to a reasonable level- but I'm still curious about what sane ballparks might be for those values? Some articles online use 64K and others recommend 512M for the same value!
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NickDec 13 '09 at 6:01

3 Answers
3

You have a server with 256M, but you can't use all of that -- remember there's some OS overhead. Add to that with the fact you're over committing as other folks have mentioned and you'll definitely thrash here. 256M is only enough for a small DB, 20 connections is a lot with what you've got configured.

1) reduce your max connections to 4 (you're using 3 out of 20)

2) optimize your query cache better; 8M is really large, and 64M total is a lot based on your hits/prunes; try a 4/32 combo and see how it goes. Really I think a 2/24 combo would work for you.

3) you have no sorts requiring temp tables, why is that max_heap_table_size verb in there? Comment that out, use the defaults

4) do you actually have 128 tables? Try cutting that table_cache in half to 64 or 48

5) reduce thread_cache_size to 4

6) optimize those tables to reduce fragmenting

Those are some things to start with. It looks like you threw a bunch of numbers in a config without any actual profiling to know what you needed and have created a mess; if all else fails go back to the defaults and get rid of your custom settings and start over using some performance tuning guides you can find on Google. Get the output of SHOW VARIABLES and SHOW STATUS, find any one of a bajillion tuning guides and plug in your actual, real numbers into their equations and that'll tell you the exact-ish numbers you need to put in your config file.

This is a old answer to an old question, but I'd like to point out that in the mysqltuner result posted by the asker the server has only been up for 40s which isn't enough time to accurately judge the loads the server will see. Ideally you would run mysqltuner a few times over the course of a day or more, and then analyze the results. Other than that your suggestions are sound.
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instanceofTomDec 16 '11 at 20:13

Now you have to check each of these values and figure out which one is responsible for this huge number. And don't trust this script unreservedly - I tried running it on one of my DB servers and it calculated that the maximum memory is 140% of the total amount of physical memory, but the system has been running for years without any stability issues.

Keep in mind that this is not 100% correct, and is in fact just an estimation, as certain settings in MySQL have no defined limit.

You can start toning down some of the settings in your config file and running the tuner again, but I'd advise getting an expert's help if you don't have time to waste changing my.cnf, restarting it and running the tuner.